How big of an inverter do I need to power a 15-amp power saw?
March 16, 2017 8:42 PM   Subscribe

I'm considering a solar-power system for my small workshop. My miter saw requires 1800 watts. Will a 2000-watt inverter be sufficient, or does the saw have a "start-up" energy requirement beyond 2000 watts?
posted by jackypaper to Technology (4 answers total) 1 user marked this as a favorite
According to this wattage worksheet, you'll need more, like, double that.
posted by at at 9:48 PM on March 16 [1 favorite]

Yeah, it will probably have a startup spike draw. 1800W is the normal max load of 15A but apparently miter saws can draw 20A+ on startup. There are lots of people online posting about popping 15A and even 20A breakers with their saws.

That said, most inverters have both a continuous as well as a peak rating - for example, this random inverter is rated for 2000W with a 4000W surge which would be more than enough. So just make sure your inverter has a decent surge rating.
posted by GuyZero at 9:53 PM on March 16 [1 favorite]

You really need to call the manufacturer because it depends on the type of 110 single phase motor.

A cheap split phase motor or induction-start/induction-run motor, develops high starting currents, approximately 700 to 1,000% of rated use.

Capacitor start/induction run motor's startup inrush is usually 450 to <600% of rated use.

A permanent split capacitor (PSC) motor usually less than 200% of rated load current to start.

I think a high dollar capacitor-start/capacitor-run motor is the same as a PSC motor. And I don't remember what a disposable shaded pole motor needs.
posted by ridgerunner at 9:54 PM on March 16

Oh yeah, you'll need to make sure your motor"s startup inrush duration is less than your inverter's surge production.
posted by ridgerunner at 10:08 PM on March 16

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